Why Does the Drum Of a Ready-Mix Concrete Truck Turn?

Ready-mix concrete trucks bring concrete right to the building site. The drum turns so that the concrete will stay well mixed and not begin to harden. If the concrete hardens it cannot be poured out of the mixer. Concrete is made from a mixture of cement, sand, gravel and water. A large building that is under construction requires large amounts of concrete at one time, usually more than is possible to mix at the construction site. That is why concrete is made all together in concrete mixing plants. The ready-mix truck's drum is kept turning as it moves from plant to site so that the concrete stays well mixed and its elements do not separate or solidify.